With increasing occurrences of open heart surgery, there has arisen the need for faster and more accurate monitoring systems for blood coagulation parameters. Heparin is the anticoagulant of choice for open heart surgery. Generally, during the extracorporeal phase of open heart surgery, heparin is administered in relatively large dosages, to achieve anticoagulation and is then neutralized with protamine, and blood products are supplied. The amount of heparin to be neutralized is currently determined by clotting methods which have been found not to determine heparin quantitatively.
It has been found that neutralization at the peak of extracorporeal circulation is very often not quantitative, with the result that small amounts of heparin remain. It has also been found that at this particular period, the antithrombin heparin cofactor is largely depleted. With the addition of blood products at this point, amounts of heparin may be present and may lead to postoperative bleeding.
The clotting process, particularly in view of these postoperative additions to the blood, provides a complex condition under which it is most desirable to rapidly and accurately determine various postoperative heparin levels.
The art therefore required a device which would rapidly perform accurate measurements of coagulation parameters on blood specimens involving consecutive reactions by using a large number of reagents.
Various attempts have been made to provide automatic blood and biological fluid analyzers, such as is disclosed in U.S. Pat. No. 3,488,156, issued Jan. 6, 1970 to Good et al.; U.S. Pat. No. 3,489,525, issued Jan. 13, 1970 to Natelson; U.S. Pat. No. 3,634,868, issued Jan. 11, 1972 to Pelavin et al.; U.S. Pat. No. 3,941,479, issued Mar. 2, 1976 to Whitehead; U.S. Pat. No. 4,030,888, issued June 21, 1977 to Yamamoto et al.; U.S. Pat. No. 4,063,309, issued Dec. 13, 1977 to Hennessy et al. and U.S. Pat. No. 4,134,678, issued Jan. 16, 1979 to Brown et al. One other prior art automated chemical diagnostic analyzer is the ATAC 3000, manufactured by Turpen Laboratories Systems, Inc., Jackson, N.J.
These prior art attempts did not provide the multiple consecutive analysis of multiple specimens in a rapid and yet accurate manner, so as to advise the physician in the operating room of certain crucial parameters, such as the blood coagulation parameters. The aforesaid prior art devices were generally limited to two sequential reactions at most.